The past few years have witnessed the beginnings of a shift in the patterns of content creation and exchange over the Internet. Previously, content, in the form of web pages, images, audio and video, was primarily created by a small minority of entities and was delivered to a large audience of web users. However, recent trends such as the rise in popularity of online social networking; the ease of content creation using digital devices like smartphones, cameras, and camcorders; and the ubiquity of Internet access, have democratized content creation. Now, individual Internet users are creating content that makes up a significant fraction of Internet traffic.
This change in the patterns of content creation is leading to a corresponding change in the patterns of content exchange. Users are much more interested in the content created or endorsed by others nearby in their social network, a fact reinforced by the associated privacy settings that allow users to restrict content visibility to their region of the social network. The net result is that, compared to content shared over the Internet just a few years ago, content today is generated by a large number of users located at the edge of the network, is of more uniform popularity and exhibits a popularity distribution that is governed by the users' social networks.
Unfortunately, existing architectures for content distribution, built to serve more traditional workloads, are ill-suited for the new patterns of content creation and exchange. The result is a mismatch between infrastructure and workload. For example, web caches have been shown to exhibit poor performance on social networking content due to the more uniform popularity of content; and many online social networking sites have moved away from content distribution networks (CDNs), and toward highly-engineered in-house delivery solutions, due to the expense and poor content hit ratios.